Space heater



F. E. FERTIG SPACE HEATER May 2, 1961 Filed July 1, 1957 INVENTOR- ala United States Patent This invention relates to a space heater, and more specifically, to an improved heater adapted to be supported within a wall for discharging heated air into a room or other space.

In the operation of a wall heater or a heater located adjacent the wall of a room, a blower is often utilized to direct a curtain of recirculated room air above the heated air discharged from the unit. Since the room air discharged outwardly and downwardly by the blower is cooler and heavier than the heated air, the heated air is forced downwardly across the floor area of the room by the curtain of cooler air thereabove. Preferably, the outwardly flowing streams of cool and warm air mix with each other and roll-across the lower part of the room to maintain a substantial-1y uniform room temperaturef However, it has been found that where the dilference in tempertaure between the room air and the heated air is relatively great, the streams of air discharged from the heater fail to mix properly, tending 'to produce cool drafts throughout the room. Since the blower also functions to circulate cool air about the heater cabinet, a temporary interruption of blower operation or a reduction in blower speed in order to eliminate the cool drafts within a room, may result in overheating of the heaters cabinet or shell.

Accordingly, one of the main objects of the present invention is to provide a structure which overcomes the above disadvantages and in which overheating of the outer casing is avoided eventhrough the blower may be ports of awall heater so as to direct the heated air from the discharge-ports downwardly towards the floor area of a room. In this connection, his a specific object to provide a structure wherein the relatively cool room air is premixed with'warm airprior'to its discharge through the, nozzle. of .a blower, thereby eliminating cool air drafts which might otherwise be produced where the differerice in temperature between the room air and the warm air discharged from the heater is substantial.

Anotherobject is to provide a wall heater structure in which overheating is prevented by the upward flow of cool air between the inner and outer casing of the heater even when the. blower-unit is idle. Thus, a limit control for preventing overheatin-g of the heater is rendered unnecessaryand the blower, if used, may be set to operate at any selected speed;

Other objects willappear fromthe specification and drawings inwliich:

Figure" l is a perspective view'of a 'wall heater and blower unit'embodying the present'invention; Figure 2 is a vbroken vertical section. showing the wall heaterflim stalled within the wall of a room and circulating means combined therewith; and Figure 3 is a broken horizontal cross section taken along line 3-3 of Figure 2.

Referring to Figure l, the numeral 10 generally designates the outer casing of a wall heater having an inlet Patented May 2, 1961 ll for the intake of relatively cool room air and an out-' let 12 for the discharge of heated air. The heater proper is illustrated in Figure 2 and is designated by the numeral 13. The upper end of the combustion heater 13 communicates with a draft hood 14 which in turn communicates with a stack 15 extending upwardly through the stud space 16 between wall panels 17 and 18. Since the above structure is entirely conventional and is well known in the art, a more detailed describtion for the purpose of describing the present invention is believed unnecessary herein; I

Within the outer casing 10 is an inner casing represented generally by the numeral 19. For insulating purposes, the inner casing is preferably provided with double walls 20 and 21 defining an insulating air space 22 therebe tween. As shown in Figure 2, the inner casing has its lower edges spaced above the floor surface and above the bottom of the outer casing 10, and may be supported within the cabinet by a depending leg 21a which restsupon sill 22a.- Theheater 13 and draft hood 14 may be supported within theair heating chamber 23 defined by the inner casing by a support bracket 23:: or by any other It should be noted that the rear of the suitable means. inner casing 19 is spaced from back wall panel 18 and that the inner and outer casings are spaced apart at their sides to provide vertical air passages 24 (Figure 3). These passages or ducts serve to convey cool room air upwardly between the respective casings and about the sides of header plate 24a for maintaining the outer casing 10 at a relatively low surface temperature, and also serve to supply partially heated air to the blower assembly, as will be described shortly.

The blower casing 25 is disposed above the outer casing or cabinet 10 and provides a chamber 26 in which a motor-driven impeller is mounted. Chamber 26 com-.

municates directly with the spaces or passages 24 theremounted upon the front wall of the casing at a suflicient distance in front of wall panel 17 so that when it is idle the impeller will not obstruct the free flow of air through chamber 26 between lower and upper ports 28 and 29.

The blower is equipped with an intake 30 disposed be-- tween the upper and lower ports and is provided with a discharge nozzle 31 which extends downwardly and outwardly at an angle in order to'direct a curtain of air over the rising stream of heated air from heater outlet 12.

The variable speed motor 27a is equipped with a manual switch 36 mounted upon the face of the casing 25;

. blower operation whenthe air within the chamber falls This switch is movable between an off position and a plurality of on positions for varying impeller speed.

In addition, the electric impeller driving means is connected in circuit with a thermostatic switch 33 secured to the inner casing and preferably disposed within one of the ducts 24 (FigureS). The temperature-responsive element of the thermostat is exposed to heated air in chamber 23 through an opening 34 extending through 7 both walls of the inner casing, and operates to interrupt below a predetermined temperature. Since thermostatic switches are well known in the artand since switch 33 is] upwardly through the ducts or passages 24 between the outer and inner casings. As the air within the ducts is warmed by contact with the outer surface of the inner casing, it flows upwardly and passes through ports,2 8

into the lower portion of chamber 26. If. the blower or impeller is idle, this' arm air discharged from the ducts continues to flow upwardly past the impeller and into the room through vents 29. Therefore, even when, the impeller is idle, this warm air discharged from the ducts ducts and blower unit conveys heat away from the inner and outer shells of the heater. The venting of warm air from between the two casings or shells thereby increases the efiiciency of the heater and prevents overheating of the unit when the blower is inoperative.

When the blower is in operation, the direction of flow through vents 29 is reversed and relatively cool room air is drawn inwardlyinto the blower chamber 26 where it mixes with the warm air discharged into the chamher through openings 28. The air. mixed within the blower chamber is then discharged through nozzle 31 by the motor-driven impeller 27. Thus, it will be observed that the premixed air flowing downwardly and outwardly from nozzle 31 is warmer than the room air but is cooler than the heated air discharged from the heater outlet 12 directly therebelow. The heated air from outlet 12 is hemmed in by the curtain of premixed air discharged from the nozzle and is drawn downwardly towards the.

floor of the room while at the same time mixing with the cooler premixed air. As the premixed air and the heated air flow downwardly away from the heater, a mixing of the two streams occurs in the lower part of the room at a point away from both the heater and the blower. Since the premixed air is warmer than the room air, undesirable drafts of cool air are not discharged from the blower even though there is a substantial diiference in the temperatures of the heated air from outlet 12 and the relatively cool air within the room.

It is apparent that when the blower is in operation,

the rate of upward flow through ducts 24 is increased because of the aspiration efiect. Consequently, the walls of the inner and outer casings are cooled by the flow of room air through ducts 24 whether the blower is idle or is in operation. Furthermore, the blower may be operated at any desired speed by selective adjustment of control switch 36 without causing overheating of the heaterunit, in contrast to conventional structures wherein high speed blower operation is requiredin order to produce the necessary cooling effect.

Since the blower unit operates to accelerate the upward flow of cooling air about the inner casing, it is apparent that blower operation is desirable where the greatest cooling eifect from the circulation of air about the casing is sought. By providing the thermostatic switch 33 in circuit with the motor 27a, the blower will automatically commence operation when the heated air within the heater chamber reaches a predetermined temperature. If desired, the thermostat circuit may be independent of the manual switch circuit so that the thermostat operates to start the blower even though the manual switch is in o position. It is also evident that the structure of the present invention may be provided with either the thermostatic switch or the manual switch, although a device having both switches is preferred.

While the structure and operation of the illustrated embodiment of the invention has been described in considerable detail, it will be understood by those skilled in the art that many of these details may be varied considerably without departing from the spirit and scope of the invention.

I claim:

1. In combination with a wall heater equipped with a casing having an inlet and an outlet for the circulation of air therethrough, a pair of side ducts extending upwardly along the sides of said casing for the upward flow of air in heat-exchange relation with the sides of said casing, each of said ducts being equipped with a cool air inlet at its lower end adapted to be arranged above a floor surface and a heated air outlet at its upper end, a blower unit disposed above, said casing, said blower unit providing an air-mixing chamber having an upper opening and communicating adjacent the lower end thereof with all of the heated air, outlets of said ducts, and a motor driven impeller disposed within said unit for drawing room air downwardly through the upper opening and heated air upwardly through said ducts and for mixing said room air and heated air within said chamber, said unit being equipped with a nozzle for directing air mixed by said impeller outwardly and downwardly above the outlet of said casing, whereby, upon operation of said impeller substantially all of the air passing upwardly through said ducts is drawn into and mixed within said chamber and the sides of said casing are cooled by the forced upward flow of air through said ducts, said mixed air being discharged from said nozzle to direct the hot air flowing from said casing outlet downwardly and outwardly into a room.

2. The structure of claim 1 in which the air-mixing chamber of said blower unit is disposed behind said impeller and in vertical alignment with said upper opening and with the heated air outlets of said ducts.

3. In a wall heater structure of the character described, a heater cabinet having an inlet and an outlet and comprising an'inner and an outer casing defining straight and substantially vertical air-flow passages extending therebetween and along the sides thereof, a combustion heater disposed within said inner casing for heating air circulating through the inner casing between said inlet and said outlet, said outer casing providing intake and discharge ports at the lower and upper ends of said vertical passages for the upward flow of room air through said passages in heat exchange relation with the sides of said inner and outer casings, and a blower unit mounted above said heater cabinet and providing a chamber communicating with all of the upper discharge ports of said passages, said blower unit also being provided with an upper opening for the intake of cool room air into said chamber, and a motor-driven impeller mounted within said unit for drawing room air downwardly through said upper opening and warm air upwardly through said side passages and for the mixing of said room air and warm air within said chamber, said unit being equipped with a nozzle for directing air mixed by said impeller outwardly from said chamber above the outlet of said heater cabinet, whereby, upon operation of said impeller substantially all of the air passing upwardly through said passages is .drawn into said chamber and the sides of said inner and outer casings are cooled by the upward flow of cooling room air through said passages.

References Cited in the file of this patent UNITED STATES'PATENTS 1,582,657 Andrews Apr. 27, 1926 2,348,127 Grimes May 2, 1944 2,402,010 Barnes June 11, 1946 2,593,759 Horn Apr. 22, 1952 2,733,704 Giwosky Feb. 7, 1956 2,770,228 Nordholt et a1 Nov. 13, 1956 2,834,279 Thompson May 13, 1958 

